RV8 head gasket measurement urgently needed

[GreenV8S]

I urgently need to know the inside diameter of the fire ring on a Rover V8 4.6 standard composite head gasket. Plus or minus half a mil would be fine. Anyone know or in a position to find out?

[350matt]

Fairly sure its Ø94.5mm as the bore is Ø94mm

Matt

[GreenV8S]

Thanks Matt.

[v8 racing]

sorry it may be a bit late but they are 95.5mm

[GreenV8S]

Thanks Rob.

[350matt]

hang on tho
whats their dimater having been compressed?
As in order to reduce the crevice volume to a minimum the plate should be as tight as possible

Matt

[Boosted LS1]

I always assume them to be 95mm which is close enough for most calcs.

Boosted.

[GreenV8S]

One has been measured at 96.04, so I've got a nice range to choose from here! I'll call it 96mm for the sake of argument, and just hope the emissions don't suffer too badly from the excess crevice volume.

[Boosted LS1]

GreenV8S said:

One has been measured at 96.04, so I've got a nice range to choose from here! I'll call it 96mm for the sake of argument, and just hope the emissions don't suffer too badly from the excess crevice volume.

Was that uncompressed?

Boosted.

[GreenV8S]

Don't know. Do they squish much when compressed?

[350matt]

Some can move quite a bit, do you have the ones that came off the engine? the trick is to have it so the edge of the gasket when compressed is flush with the spacer. Either more or less wil create crevice volume and if its too tight (protruding into the chamber) it'll also create a hot spot and may melt and fall off.

Matt

[Boosted LS1]

GreenV8S said:

Don't know. Do they squish much when compressed?

Well that measurement seems to large. I'd expect 1mm over bore diameter to be normal. The big measurement you suggest is almost buick 300 territory with felpro's.

Boosted.